This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Campylobacter jejuni is the most common bacterial enteric pathogen in the United States and worldwide. Hawaii has the highest incidence of Campylobacter-caused gastroenteritis in the country. Infection with C. jejuni is also associated with autoimmune sequelae, particularly the development of paralytic Guillain-Barr[unreadable] Syndrome. Little is known about either the molecular or the immunological mechanisms of pathogenesis . In an earlier cooperative study with the Hawaii State Department of Health, we collected a large number of Campylobacter strains from clinical, food, animal, and environmental sources. Some of these strains are known to be pathogenic and others are of attenuated virulence. We propose to type these strains with respect to a number of putative virulence genes that have been proposed to govern the adherence, internalization, and secretion properties of C. jejuni. We will also make specific antibody reagents that will allow the serotyping of local isolates as well as the isolation and analysis of C. jejuni virulence-associated antigens. The virulence attributes of the genetically and serotypically typed organisms will be tested against human epithelial cells in tissue culture. Understanding the role of these virulence genes and the surface attachment and internalization molecules of C. jejuni may lead to new prevention and treatment strategies.